RFR: 8313249: Fix -Wconversion warnings in verifier code [v5]

[Coleen Phillimore]

> See bugid for comments.  Most of the verifier code deals with ints, so the u2 and other parameters weren't really needed and can be promoted to int. Mostly types are changed, but a few checked_cast<>s are added.
> Tested with tier1-4, sanity Oracle platforms.

Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:

  Dean's comments.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15056/files
  - new: https://git.openjdk.org/jdk/pull/15056/files/cabd399d..f877b58f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15056&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15056&range=03-04

  Stats: 4 lines in 3 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/15056.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15056/head:pull/15056

PR: https://git.openjdk.org/jdk/pull/15056